Rapid, low-cost colorimetric detection of <i>Salmonella</i> Typhi bacteriophages for environmental surveillance
Typhoid fever, caused by <i>Salmonella</i> Typhi, remains a significant global health threat, particularly in low-resource settings with inadequate sanitation. Effective control measures, such as vaccines, require precise data on where typhoid is most prevalent, yet current surveillance methods are expensive and limited in scope. This study introduces a rapid, low-cost, and scalable colorimetric assay for detecting S. Typhi bacteriophages (viruses that infect bacteria) in environmental water samples. Unlike traditional methods, this test detects the presence of S. Typhi indirectly by identifying associated phages, offering a specific and sensitive approach for monitoring typhoid fever circulation. The assay was validated in diverse settings across four countries and demonstrated high accuracy and cost efficiency. By reducing reliance on expensive laboratory equipment and complex procedures, this tool makes typhoid surveillance more accessible, especially in low-income regions, helping prioritize vaccination campaigns and improve public health interventions.
Authors
- Dipesh Tamrakar (ORCID: https://orcid.org/0000-0002-0772-3653)
- Richelle C. Charles (ORCID: https://orcid.org/0000-0002-8881-1849)
- Takashi Yokoyama
- Késia Esther da Silva (ORCID: https://orcid.org/0000-0001-8593-1119)
- E. G. Mulder
- Paulo César Pereira dos Santos (ORCID: https://orcid.org/0000-0001-5470-6314)
- Karla N. Fisher
- Katherine Shafer
- Kathleen M. Neuzil (ORCID: https://orcid.org/0000-0001-9480-2714)
- Shiva Ram Naga
- Jean T. Coulibaly (ORCID: https://orcid.org/0000-0002-3626-6068)
- Eric J. Nelson (ORCID: https://orcid.org/0000-0003-2649-2624)
- Jason Randolph Andrews (ORCID: https://orcid.org/0000-0002-5967-251X)
- Makhan Maharjan
- Isaac I. Bogoch (ORCID: https://orcid.org/0000-0003-1590-6748)
- Rajeev Shrestha (ORCID: https://orcid.org/0000-0001-8233-3754)
- Mi Yang (ORCID: https://orcid.org/0000-0003-0366-4390)
- Mohammed S. Yusuf (ORCID: https://orcid.org/0000-0003-4278-3229)
- Brad-Lot Igiraneza
Institutions
- Universidade Federal de Mato Grosso do Sul (BR)
- National Institutes of Health (US)
- University Health Network (CA)
- Harvard University (US)
- Oregon Health & Science University (US)
- University of Toronto (CA)
- Dhulikhel Hospital (NP)
- University of Florida Health (US)
- Toronto General Hospital (CA)
- University of Florida (US)
- Massachusetts General Hospital (US)
- Hôpital régional (CH)
- Swiss Centre for Scientific Research (CI)
- Kathmandu University (NP)
- Université Félix Houphouët-Boigny (CI)
- Fogarty International Center (US)
- Stanford University (US)
Publication Details
- Journal
- mBio
- Published
- 2025-08-18
- DOI
- https://doi.org/10.1128/mbio.01963-25
- Citations
- 3
- Primary Topic
- Salmonella and Campylobacter epidemiology
- Type
- article
- Field-Weighted Citation Impact
- 3.49
Funders
- Bill and Melinda Gates Foundation
- Stanford University Center for Innovation in Global Health